[ rahy-sin, ris-in ]
/ ˈraɪ sɪn, ˈrɪs ɪn /

noun Chemistry.

a white, poisonous, protein powder from the bean of the castor-oil plant.

Nearby words

  1. richter, burton,
  2. richter, conrad,
  3. richter, sviatoslav,
  4. richthofen,
  5. richweed,
  6. ricinoleic,
  7. ricinoleic acid,
  8. ricinolein,
  9. ricinus oil,
  10. rick

Origin of ricin

1895–1900; < New Latin Ricinus name of genus, Latin: castor-oil plant

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ricin

British Dictionary definitions for ricin


/ (ˈraɪsɪn, ˈrɪs-) /


biochem a highly toxic protein, a lectin, derived from castor-oil seeds: used in experimental cancer therapy

Word Origin for ricin

C19: from New Latin Ricinus genus name, from Latin: castor-oil plant

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for ricin



poison obtained from the castor-oil bean, 1888, from ricinus, genus name of the castor-oil plant (1694), from Latin ricinus (Pliny), of uncertain origin, perhaps the same word as ricinus "tick" (in sheep, dogs, etc.).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for ricin


[ rīsĭn, rĭsĭn ]


A poisonous protein that is extracted from the castor bean and is used as a biochemical reagent.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for ricin


[ rīsĭn, rĭsĭn ]

An extremely poisonous protein extracted from the castor bean. Ricin inhibits protein synthesis in cells, and is used as a biochemical reagent and in cancer research.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.